# Questions tagged [integer]

For challenges involving the manipulation of integers.

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### Even sum subarrays

Given an array of integers, count the number of contiguous subarrays with an even sum. You may assume that the array is non-empty, and contains only non-negative integers. This is code-golf, so the ...
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### Is it an elementary matrix?

Consider a linear system of equations, in $n$ unknowns, expressed as $$A \textbf x = \textbf b$$ where $A \in M_{n,n}(\mathbb Z)$ is an $n \times n$ matrix of integers, $\textbf x$ is a column ...
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### Bijective meets mixed base

Background A bijective base $b$ numeration, where $b$ is a positive integer, is a bijective positional notation that makes use of $b$ symbols with associated values of $1,2,\cdots,b$. ...
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### Narcissistic loop lengths

A narcissistic number is a natural number which is equal to the sum of its digits when each digit is taken to the power of the number digits. For example $8208 = 8^4 + 2^4 + 0^4 + 8^4$, so is ...
Inspiration Given a positive integer $1 \le n \le 9$, output all positive $n$-digit integers $i$ for which the following is true: Each digit from $1$ to $n$ appears exactly once in $i$. ...
Let's consider the sequence $S$ consisting of one $1$ and one $0$, followed by two $1$'s and two $0$'s, and so on: $$1,0,1,1,0,0,1,1,1,0,0,0,1,1,1,1,0,0,0,0,...$$ (This is A118175: Binary ...